Cutting wire for removal of expanded material after curing of a composite part

Abstract

Composite fabrication system and associated methods. In one embodiment, a composite fabrication system comprises a molding tool that includes a forming surface at least partially disposed within a constrained space, and a foamable material that expands inside of the constrained space to form an expanded material that presses a layup of one or more composite layers against the molding tool. The composite fabrication system further comprises a curing device configured to cure the layup to form a composite part, and a cutting wire embedded in the constrained space that is heated and configured to cut the expanded material into pieces that are removable from the constrained space.

The invention claimed is: 
     
       1. A method of fabricating a composite part, the method comprising:
 placing one or more composite layers on a molding tool to form a layup, wherein at least a portion of the layup is within a constrained space; 
 activating a foamable material to expand into an expanded material within the constrained space; 
 curing the layup while the expanded material presses the layup against the molding tool to form the composite part; 
 boring a hole through the expanded material after curing; 
 threading a cutting wire through the hole in the expanded material; 
 controlling a manipulator comprising a robotic arm, with a controller, to perform automated tasks of:
 grasping opposing ends of the cutting wire with end effectors that make an electrical coupling with the cutting wire; 
 heating the cutting wire with current applied through the cutting wire via the electrical coupling; and 
 moving the cutting wire within the constrained space to cut the expanded material into pieces; and 
 
 removing the pieces from the constrained space. 
 
     
     
       2. The method of  claim 1  wherein activating the foamable material comprises:
 heating the foamable material. 
 
     
     
       3. The method of  claim 1  wherein boring a hole through the expanded material comprises:
 boring the hole with a heated bit that extends through the expanded material. 
 
     
     
       4. The method of  claim 1  wherein heating the cutting wire comprises controlling the manipulator further comprises controlling the manipulator with the controller to perform the automated task of:
 pushing or pulling the cutting wire through the hole with the manipulator. 
 
     
     
       5. The method of  claim 1  wherein:
 the cutting wire comprises a single cutting wire; and 
 moving the cutting wire comprises moving the cutting wire with the manipulator in a pattern within the constrained space to segment the expanded material into the pieces. 
 
     
     
       6. The method of  claim 1  wherein:
 the foamable material comprises foamable pellets. 
 
     
     
       7. The method of  claim 1  wherein removing the pieces from the constrained space comprises:
 controlling the manipulator with the controller to perform the automated task of:
 grasping the pieces with the manipulator; and 
 pulling the pieces from the constrained space with the manipulator. 
 
 
     
     
       8. The method of  claim 1  wherein removing the pieces from the constrained space comprises:
 applying suction with a vacuum device to remove the pieces. 
 
     
     
       9. The method of  claim 1  wherein:
 the composite part is manufactured for an aircraft. 
 
     
     
       10. A method of fabricating a composite part, the method comprising:
 placing composite layers on a molding tool to form a layup, wherein at least a portion of the layup is within a constrained space created by a shape of the molding tool; 
 heating the molding tool and the layup in a curing device, wherein the heating activates a foamable material to expand within the constrained space into an expanded material that presses the layup against the forming surfaces of the molding tool, and cures the layup to form the composite part; 
 boring a hole through the expanded material after curing; 
 threading a cutting wire through the hole in the expanded material; 
 controlling a manipulator comprising a robotic arm, with a controller, to perform automated tasks of:
 grasping opposing ends of the cutting wire with end effectors that make an electrical coupling with the cutting wire; 
 heating the cutting wire with current applied through the cutting wire via the electrical coupling; and 
 moving the cutting wire while heated within the constrained space to cut the expanded material into pieces; and 
 
 removing the pieces from the constrained space. 
 
     
     
       11. The method of  claim 10  wherein:
 the cutting wire comprises a single cutting wire; and 
 moving the cutting wire comprises moving the cutting wire with the manipulator in a pattern within the constrained space to segment the expanded material into the pieces. 
 
     
     
       12. A composite fabrication system, comprising:
 a molding tool that includes a forming surface upon which one or more composite layers are placed to form a layup, wherein at least a portion of the forming surface is disposed within a constrained space; 
 a foamable material activated to expand into an expanded material within the constrained space; 
 a curing device configured to cure the layup while the expanded material presses the layup against the molding tool to form a composite part; and 
 a removal tool configured to bore a hole through the expanded material after curing, and comprising a cutting wire threaded through the hole in the expanded material, and a manipulator comprising a robotic arm and controlled with a controller to perform automated tasks of:
 grasping opposing ends of the cutting wire with end effectors that make an electrical coupling with the cutting wire; 
 heating the cutting wire with current applied through the cutting wire via the electrical coupling, and 
 moving the cutting wire within the constrained space to cut the expanded material into pieces; 
 
 the removal tool is configured to remove the pieces from the constrained space. 
 
     
     
       13. The composite fabrication system of  claim 12  wherein the manipulator is further controlled with the controller to perform the automated task of:
 grasping the pieces, and pulling the pieces from the constrained space. 
 
     
     
       14. The composite fabrication system of  claim 12  wherein the manipulator is controlled with the controller to perform the automated task of:
 pushing or pulling the cutting wire through the hole. 
 
     
     
       15. The composite fabrication system of  claim 12  wherein:
 the cutting wire comprises a single cutting wire; and 
 the manipulator is configured to move the cutting wire in a pattern within the constrained space to segment the expanded material into the pieces. 
 
     
     
       16. The composite fabrication system of  claim 12  wherein:
 the foamable material comprises foamable pellets. 
 
     
     
       17. The composite fabrication system of  claim 12  wherein the removal tool comprises:
 a drill configured to bore the hole through the expanded material after curing. 
 
     
     
       18. The composite fabrication system of  claim 17  wherein:
 the drill is configured to bore the hole with a heated bit that extends through the expanded material. 
 
     
     
       19. The composite fabrication system of  claim 12  wherein the removal tool comprises:
 a vacuum device configured to apply suction to remove the pieces. 
 
     
     
       20. The composite fabrication system of  claim 12  wherein:
 the composite part is manufactured for an aircraft.